1. Technical Field
This disclosure relates generally to mounting hardware for securing warning light arrays to motor vehicles, and more particularly, to a mounting foot assembly for securing a lightbar to the roof of a motor vehicle.
2. Background
Lighting systems for mounting on the exterior of police and other public service vehicles have long been known in the art. Exterior mounting of such lighting systems is generally preferred in order to enhance the visibility thereof, i.e., a warning light mounted above the roof of an emergency vehicle may be more readily seen than a light mounted below the vehicle roof line or within the vehicle. Such exterior mounting also affords the possibility of the emitted light being seen from any direction and minimizes the possibility that the light produced by the lighting system will interfere with the vision of the vehicle operator.
A long-standing problem associated with lightbar assemblies resides in mounting the assembly to the vehicle in such a manner that it may be easily positioned as desired on the vehicle and, most importantly, will not become loose due to vibration or other causes and either change position or become dislodged. There are, of course, many mounting assemblies known in the prior art for attaching devices to the roof of a motor vehicle. U.S. Pat. No. 4,588,118 (hereinafter the '118 patent), assigned to the assignee of the present invention, discloses a mounting foot assembly for securing a lightbar to the exterior of a motor vehicle. Specifically, the mounting foot assembly includes a mounting member foot portion and gutter clamp which supports the mounting member in clamped relationship to a rain gutter of the motor vehicle. An upwardly projecting portion of the mounting member has laterally projecting tabs for engagement with inwardly facing longitudinal slots defined by an I-beam extruded aluminum strength member. The mounting foot assembly includes locking cams configured to extend outwardly to engage the bottom of the longitudinal slots. When secured in their engaged position, the locking cams secure respective of the mounting members to the I-beam and urge the corresponding gutter clamp inwardly to secure the mounting foot assembly to the gutters at the opposite sides of the vehicle.
While the lightbar mounting foot assembly disclosed in the '118 patent has been commercially successful and provided a secure engagement between the lightbar and the motor vehicle, further improvements in lightbar mounting are possible. For example, modern motor vehicle design has eliminated the outwardly projecting rain gutter and thus a convenient clamping location. Further, reinforced plastic materials may be used to form a mounting foot having improved efficiency of manufacture and aesthetic appearance. These changes result in the need for a new and effective mounting foot assembly that is compatible with modern vehicle configurations and mounting foot materials.
The lightbar disclosed in the '118 patent, as well as that disclosed in U.S. Pat. No. 5,027,260 (hereinafter the '260 patent), also assigned to the assignee of the present invention, are constructed around a longitudinally extending extruded aluminum strength member. This strength member may be in the form of an I-beam as shown in the '118 patent, a concave channel as shown in the '260 patent, or the like. Extrusion is an efficient method for obtaining a strength member of high rigidity having a complex sectional configuration. Longitudinally extending features are arranged for the mounting of lightheads, internal components such as power supplies to the interior of the extrusion and exterior components such as lenses to the exterior of the extrusion.
Typically, components are engaged with longitudinal features defined by the extrusion and slid along the length of the extrusion into a desired position where they are secured in place by set screws bearing against the extrusion. Brackets or mounting feet for a lightbar have been fixed to the bottom exterior surface of the lightbar strength member in a similar manner. Lightbars are typically assembled according to a customer's specification and shipped to the customer for installation on a motor vehicle. In a fully assembled lightbar, end caps may cover entry openings for all of the longitudinally extending features, including the inwardly facing slots configured to receive the upper portions of mounting brackets or mounting feet. In such a lightbar, the feet must be mounted to the lightbar prior to installation of the end caps or the lightbar must be partially disassembled by the end user to accommodate mounting of the support foot or mounting bracket. Shipping a lightbar with the mounting feet attached increases the cost of shipping and also increases the likelihood of breakage during shipment. End user disassembly and re-assembly of lightbar components to the extrusion complicates lightbar installation.
U.S. Pat. No. 6,845,893, the disclosure of which is incorporated herein by reference in its entirety, discloses a light bar mounting foot that is compatible with an extruded light bar strength member and which does not require disassembly of the light bar for mounting. The patent discloses various features of attaching and locking the mounting foot to the light bar strength member.
In recent years the roof line of some models of vehicles have changed in appearance in that the roof has incorporated more longitudinal curvature over its length. To the extent that the roof line slopes in a longitudinal direction either upwardly or downwardly in the area in which a light bar is to be installed, with a fixed mounting foot, the lights on the light bar will tend to be aimed incorrectly, either too high or too low.
In some instances, a light unit, such as an alley light, may be attached to the ends of the lightbar. Such light units commonly utilize halogen bulbs as the light source, and heat from the halogen bulb may build up within the lightbar unit itself.
There is a need for a mounting foot for a lightbar which is compatible with the light bar strength member, which is easily assembled, and which can provide for variations is the longitudinal slope of the vehicle roof. Additionally, there is a need for an arrangement by which a light unit may be supported by the mounting foot to provide a side light, thereby eliminating the need to mount a light unit of the type that generates a large amount of heat within the lightbar itself.